A ball with a mass of $9 kg$ moving at $14 m/s$ hits a still ball with a mass of $18 kg$ . If the first ball stops moving, how fast is the second ball moving?

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Answer 1 · 2015-12-23T03:45:31

If the second ball is in rest before collision then after collision velocity of the second ball is 7m/s.

Answer 2 · 2015-12-23T04:23:28

$7$ $m$ / $s$

$M_1$ = mass of first ball, $V_1$ = velocity of first ball
$M_2$ = mass of second ball, $V_2$ = velocity of second ball

by conservation of linear momentum

$M_1V_1 +M_2V_2=M_1V_1+M_2V_2$

9 x 14 + 18 x 0 = 9 x 0 + 18 x $V_2$

therefore $V_2$ = $(9 " x " 14)/18$ = $7$ $m$ / $s$

A ball with a mass of 9 kg9 kg moving at 14 m/s14 m/s hits a still ball with a mass of 18 kg18 kg. If the first ball stops moving, how fast is the second ball moving?